In an electrophoretic display apparatus and magnetophoretic display apparatus for displaying a desired picture by using the microcapsules, each sealing colored dispersion media and the electrophoretic particles, the uniform arrangement of the microcapsules over a substrate is important on a stable display operation.
Conventionally, many methods with an object of producing a pressure sensing paper and a heat sensitive paper are proposed an methods of uniformly coating microcapsules on a plane surface.
For instance, the Japanese Patent No. 1545227 discloses a method of producing a pressure sensing copying paper by a free fall vertical curtain method as a preferable method than an air knife or blade coating method.
Also, the Japanese Patent No. 1376224 discloses a hopper typed coating apparatus as a similar method.
Further, the Japanese unexamined patent publication No. 57-27172 discloses a method to spray microcapsules coating liquid to a web (a support body) which runs continuously and to obtain a coating layer of continuous constant thickness by leveling this with a leveling device.
Moreover, the Japanese unexamined patent publication No. 62-138284 discloses a method in which a bonding layer is formed over a substrate, microcapsules layer is formed thereon, and the non-contacted microcapsules with the bonding layer are separated by gravity to form an uniform microcapsules layer of a single layer.
However, the aforementioned methods are for the purpose of obtaining the uniform layer of microcapsules, and are not sufficient methods for forming the microcapsules layer used in the display panel.
Properly placing the microcapsules at positions corresponding to electrodes or magnetic poles, configuring a display pixel in the display panel, is important to display a high definition image with uniform for each pixel. The display panel must form a uniform microcapsules layer and also control an arrangement place of each microcapsules.
Particularly, when trying to display in colors, it is necessary to place a number of microcapsules of different display colors for each pixel and control each individually. To carry out such control, the microcapsules of each display color has to be placed selectively, accurately, and with high precision, the arrangement of the microcapsules must be carried out at a higher precision.
At this point, a method of placing the microcapsules at a desired position selectively and accurately is not proposed in any method as aforementioned, and no such method exists except herein.